Abstract

We have studied the depth and spatial profiles of vacancies in Czochralski‐grown silicon wafers by positron annihilation spectroscopy. By using a variable energy positron beam and γ‐ray spectroscopy, we have obtained depth profiles of defects in as‐grown, annealed, and 〈100〉 epitaxial Si wafers. We discuss these results in terms of vacancies and oxygen precipitates. The bulk position lifetime measurements, made as a function of axial displacement of a positron source, resolve vacancies, and divacancies in the wafer.